The center of a circle is located at (−2, 7) . The radius of the circle is 2. What is the equation of the circle in general form?

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Answer 1 · 2017-05-11T14:45:28

D

D.
It is explained already by another contributor

Answer 2 · 2017-05-11T14:52:29

The answer is the last one, $x^2+y^2+4x-14y+49=0$

We need

$(a+b)^2=a^2+2ab+b^2$

$(a-b)^2=a^2-2ab+b^2$

The equation of a circle, center $(h,k)$ and radius $=r$ is

$(x-h)^2+(y-h)^2=r^2$

Here, the center is $(-2,7)$ and the radius is $=2$

The equation of the circle is

$(x+2)^2+(y-7)^2=4$

$x^2+4x+4+y^2-14y+49-4=0$

$x^2+y^2+4x-14y+49=0$